diff options
| author | Thomas Gleixner <tglx@linutronix.de> | 2021-10-22 01:55:09 +0300 |
|---|---|---|
| committer | Borislav Petkov <bp@suse.de> | 2021-10-26 11:18:09 +0300 |
| commit | c33f0a81a2cf3920465309ce683534751bb86485 (patch) | |
| tree | bc4f3638b7a069ff3bc7072f3d9207ee101253b5 /arch/x86 | |
| parent | 6f6a7c09c4065a5b140194dfcfe4cf7104fec4d2 (diff) | |
| download | linux-c33f0a81a2cf3920465309ce683534751bb86485.tar.xz | |
x86/fpu: Add fpu_state_config::legacy_features
The upcoming prctl() which is required to request the permission for a
dynamically enabled feature will also provide an option to retrieve the
supported features. If the CPU does not support XSAVE, the supported
features would be 0 even when the CPU supports FP and SSE.
Provide separate storage for the legacy feature set to avoid that and fill
in the bits in the legacy init function.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20211021225527.10184-6-chang.seok.bae@intel.com
Diffstat (limited to 'arch/x86')
| -rw-r--r-- | arch/x86/include/asm/fpu/types.h | 7 | ||||
| -rw-r--r-- | arch/x86/kernel/fpu/init.c | 9 |
2 files changed, 13 insertions, 3 deletions
diff --git a/arch/x86/include/asm/fpu/types.h b/arch/x86/include/asm/fpu/types.h index c3ec56279767..595122fcaf51 100644 --- a/arch/x86/include/asm/fpu/types.h +++ b/arch/x86/include/asm/fpu/types.h @@ -503,6 +503,13 @@ struct fpu_state_config { * be requested by user space before usage. */ u64 default_features; + /* + * @legacy_features: + * + * Features which can be reported back to user space + * even without XSAVE support, i.e. legacy features FP + SSE + */ + u64 legacy_features; }; /* FPU state configuration information */ diff --git a/arch/x86/kernel/fpu/init.c b/arch/x86/kernel/fpu/init.c index 7074154131e6..621f4b6cac4a 100644 --- a/arch/x86/kernel/fpu/init.c +++ b/arch/x86/kernel/fpu/init.c @@ -193,12 +193,15 @@ static void __init fpu__init_system_xstate_size_legacy(void) * Note that the size configuration might be overwritten later * during fpu__init_system_xstate(). */ - if (!cpu_feature_enabled(X86_FEATURE_FPU)) + if (!cpu_feature_enabled(X86_FEATURE_FPU)) { size = sizeof(struct swregs_state); - else if (cpu_feature_enabled(X86_FEATURE_FXSR)) + } else if (cpu_feature_enabled(X86_FEATURE_FXSR)) { size = sizeof(struct fxregs_state); - else + fpu_user_cfg.legacy_features = XFEATURE_MASK_FPSSE; + } else { size = sizeof(struct fregs_state); + fpu_user_cfg.legacy_features = XFEATURE_MASK_FP; + } fpu_kernel_cfg.max_size = size; fpu_kernel_cfg.default_size = size; |